Create a cheap hardware box that connects to peoples tvs and brings them an online casino/poker. The box connects and runs over TOR. The user can deposit to his account via his computer's bitcoin client. The box is of course free.

Nuclear mining operation either in a power plant or in a submarine. It will already have a water cooling system set up for the fuel rods which can be used for the mining rigs as well. Any excess electricity generated can also be sold for more profit.

Radioactive video cards FTW. Also, nuclear power plants use steam cooling, which is kind of hot for a video card.

Just like the Bitcoin Ad network above we need a large affiliate Ad network like the likes of Commision junction, Maxbounty, Clickbank, etc. The network would be 100% Bitcoin based. The advertisers would pay in Bitccoin and publishers and affiliates would get paid in Bitcoins. The ad network should be a general purpose network offering a wide range of products and services for promotion.

I started on #3; you can check it out at JupeB.com. It doesn't have good looks or all of the bells and whistles of the big guys, but it can definitely get there. I'm in the process of bootstrapping it up now..